With smoky outdoor conditions increasing through the day, the Allegheny County Health Department on Thursday afternoon updated its air quality rating to Code Maroon — the most severe status in the U.S. Air Quality Index system — and recommended that everyone in the county remain indoors and avoid physical activity through the night and potentially through Friday.
Under the rare Code Maroon alert, air-quality conditions are considered to be “hazardous,” and all people are susceptible to their ill effects. The county issued the Maroon alert at 4 p.m., after previously upgrading it from Code Red to Code Purple earlier in the afternoon. Afternoon air conditions also prompted the city of Pittsburgh to close its public swimming pools for the rest of the day.
Until the Code Maroon alert is lifted, the health department advises that all people should avoid physical activity outdoors, and that children, elderly people and people with respiratory illnesses or other conditions should remain indoors, keep activity levels low and avoid air from outdoors.
Also Thursday afternoon, the state Department of Environmental Protection issued a statewide Code Purple alert, warning of “very unhealthy” conditions. During Code Purple alerts, all people should avoid long or intense outdoor activities, and children, elderly people and people with respiratory illnesses should avoid outdoor activities, the DEP said. The agency also encouraged all Pennsylvania residents to move activities indoors.
Smoke from wildfires in Ontario, Canada and Minnesota continues to affect Pennsylvania, significantly deteriorating the air quality across Commonwealth. The wildfire smoke will remain in the area this afternoon but is expected to eventually move out of the area on Saturday.
At 8 a.m. on Thursday, July 16, 2026, the U.S. Environmental Protection Agency’s airnow.gov site showed high levels of air pollution from wildfire smoke in northern and eastern Pennsylvania.
Residents can monitor local air quality via the U.S. Environmental Protection Agency’s Air Now website. The EPA also maintains a fire and smoke map that shows the location of fires and smoke plumes.
Allegheny County also issued a Mon Valley Episode warning shortly before 6 p.m. Thursday, saying 24-hour air-quality standards had been exceeded at an official monitoring station in the valley and were likely to continue for the next 24 hours. During an episode, companies in the Mon Valley that contribute large shares of the region’s particulate matter pollution are required to temporarily reduce activities that produce emissions.
Some of the facilities subject to the 2021 Mon Valley Episode Rule include U.S. Steel’s Clairton, Edgar Thompson and Irvin plants.
The county previously had issued a Mon Valley Watch for both days. Under a watch, those Mon Valley companies must ensure equipment is functioning properly and must have sufficient staff and resources available to act on their pollution mitigation plans.
Outside of the large companies subject to the Mon Valley rule, residents and business are encouraged to avoid contributing additional air pollution in the region while the air quality alerts are in effect. Sources of particulate matter pollution include gas-powered lawn equipment and vehicles.
Cindi Lash of WESA contributed to this report.